Illuminating glassware and method of making it



June 12, 1956 'r. s. O'LEARY 2,

ILLUMINATING GLASSWARE AND METHOD OF MAKING IT Filed April 24, 1955 i 4/6/97 ABJORBl/VG Mfif'f/AL INVENTOR. 77/0/14: 025427 WLM JITTORNEY.

United States Patent ILLUMINATING GLASSWARE AND METHOD OF MAKING IT Thomas G. OLeary, Corning, N. Y., assignor to Corning Glass Works, Corning, N. Y., a corporation of New York Application April 24, 1953, Serial No. 350,815

3 Claims. (Cl. 88-1) This invention relates to illuminating glassware comprising a sheet or hollow glass body having translucent portions forming indicia such as louvers and decorative designs and adapted to be illuminated from the side opposite the observer. It relates particularly to such glass sheets having linear translucent louvers for the directional control of transmitted light, such as window panes, ceiling fixtures and illuminating panels.

Such an article comprises a monolithic glass body composed of a photosensitively opacifiable glass such as the glasses described and claimed in Patents Nos. 2,515,940, 2,515,941, 2,515,943, 2,651,145, and 2,684,911. The translucent portions are formed by photothermal development or by exposing selected portions of the glass body to short-wave raditions and thereafter heating the glass body to cause precipitation in the exposed portions of light-diffusing crystallites which render such portions translucent. As will be appreciated, such translucent portions extend inwardly from a surface of the glass body, usually entirely therethrough.

With a high intensity of illumination, as for instance where strong sunlight falls directly on such a louvered window pane, an objectionable glare is emitted from the surface of the translucent portions opposite the source of light and may be so intense as to cause visual discomfort or interfere with vision through the window. It is believed that such excessive emission of light by the translucent portions or louvers is a manifestation of the wellknown principle of the release of trapped light from within the glass by light-reflecting particles or facets within or on the surface of the glass. Be that as it may, however, the reduction of such glare without reduction of visibility through the clear transparent portions of the glass is highly desirable.

I have now discovered that such glare can be effectively diminished without decreasing the transmission of light or the visibility through the transparent portions by removing the translucent portions to a desired depth to form depressions in the surface of the glass body in mg ister with the translucent portions and introducing into the resulting depressions a light-absorbing material such as a paint, enamel, or plastic containing a light-absorbing or selectively reflecting pigment or dye.

The present invention is illustrated in the accompanying drawing wherein:

Fig. 1 is a plan view of a transparent glass sheet having linear translucent strips in accordance with the invention, the thickness of the sheet and the strips being exaggerated for convenience.

Fig. 2 is an enlarged, fragmentary sectional view on the line 22 of Fig. 1, showing the etched-out portions of the strips containing a light-absorbing material.

The spaces between the translucent strips are clear and transparent and are of such width as to render the translucent strips effective as louvers. While such strips are shown in a position perpendicular to the face of the sheet, they may, if desired, be arranged at an angle to the face. Also instead of being merely parallel to each other, simiice fusing crystallites of lithium metasilicate, lithium disilicate or an alkali metal fluoride when exposed to shortwave raditions and subsequently heated, which type of glass is described in the aforementioned Patents Nos. 2,515,940, 2,515,943, 2,651,145, and 2,684,911, is exposed to such radiations through a photographic transparency or suitable screen and is thereafter heated to form in the exposed areas translucent indicia such as louvers or decorative designs, which preferably extend entirely through the sheet, the unexposed areas remaining transparent. In such a glass body, the translucent portions are substantially more soluble in dilute aqueous hydrofluoric acid than the transparent portions, which are substantially unaffected thereby, as is shown in Patent No. 2,628,160. Accordingly the partially translucent glass sheet is treated with a dilute aqueous solution of hydrofluoric acid to dissolve the translucent portions to any desired depth, say 0.1 to 1 mm., below one surface of the sheet. The depressions so formed in such surface of the glass sheet are obviously in register with the undissolved remainder of the translucent portions. Areas of the sheet which it is desired to protect against the action of the acid, such as its rear surface, may be coated with wax which can be removed after the etching is completed.

As light-absorbing materials to be introduced into the etched-out depressions in the glass body, a variety of materials including virtually any inorganic pigment may be employed, depending on the degree of masking and the color effect desired. I have found finely divided carbon particularly useful for producing a neutral or gray color of substantially uniform spectral transmission. Other pigments such as metallic oxides or sulfides may be used where a particular color or tint may be desired.

While strongly light-absorbing and adherent materials such as finely divided carbon can be utilized without a binder, it is generally preferable to disperse the colorant in a solid carrier, for example, a thermosetting resin. To act as a binder, the resin must of course be appropriately cured. The depressions are preferably completely filled to provide a fiat planar surface which can be easily cleaned. Alternatively the coloring material may be dispersed in an easily fusible ceramic material such as a powdered glaze or enamel, the depressions filled with such mixture, and the glass body subsequently fired to fuse the ceramic carrier. Care must be taken, however, to secure a proper expansion match of the ceramic with the glass.

While the etched-out portions of the strips may, according to the preferred embodiment of the invention, be removed by solution with dilute aqueous hydrofluoric acid as described above, they may also, if desired, be removed by grinding, in which case the photosensitively opacifiable glasses described in the above-mentioned Patent No. 2,515,941 may also be utilized.

What is claimed is:

1. The method of reducing glare from the translucent portions of a light-directing article comprising a glass body composed of a photosensitively opacifiable glass, selected portions of the glass body having been exposed to short-wave radiations and the glass body thereafter having been heated to develop in such portions light-diffusing crystallites rendering such portions translucent, such translucent portions extending inwardly from a surface of the glass body, which comprises removing the translucent portions to a desired depth to form depressions in such surface of the glass body in register with the translucent portions, and introducing into the depressions a light-absorbing material.

2. The method of reducing glare from the translucent portions of a light-directing article comprising a glass body composed of a photosensitively opacifiable glass, selected portions of the glass body having been exposed to short-wave radiations and the glass body thereafter having been heated to develop in such portions light-diffusing crystallites selected from the class consisting of a lithium silicate and an alkali metal fluoride, such crystallites rendering such portions translucent, such translucent portions extending inwardly from a surface of the glass body, the remainder of the glass body being transparent, which comprises treating the glass body with a dilute aqueous solution of hydrofluoric acid to dissolve the translucent portions to a desired depth to form depressions in such surface of the glass body in register with the translucent portions, the remaining portions being substantially unaffected, and introducing into the depressions a light-absorbing material.

3. A louver device comprising a monolithic glass sheet having a plurality of sharply defined, parallel, translucent, linear portions containing light-diffusing crystallites and extending through the sheet to form a series of louvers,

said portions being depressed in one surface of the'sheet, said depressions containing a substantially opaque lightabsorbing material dispersed in a solid carrier and capable of absorbing and reflecting a substantial proportion of the light traveling through said portion in a direction toward the side of said sheet having the depressions from a light source on the opposite side, whereby the eyes of a viewer on the side of the sheet having said depressions are substantially shielded by said opaque material against glare incident to the diffusion of light by said crystallites.

References Cited in the file of this patent UNITED STATES PATENTS 1,244,734 Higgins Oct. 30, 1 917 1,494,630 Reizenstein May 20, 1924 2,053,173 Astima Sept. 1, 1936 2,515,940 Sto0key July 18, 1950 2,515,943 Stookey July 18, 1950 2,628,160 Stookey Feb. 10, 1953 FOREIGN PATENTS 458,509 Great Britain Dec. 14, 1936 

3. A LOUVER DEVICE COMPRISING A MONOLITHIC GLASS SHEET HAVING A PLURALITY OF SHARPLY DEFINED, PARALLEL, TRANSLUCENT, LINEAR PORTIONS CONTAINING LIGHT-DIFFUSING CRYSTALLITES AND EXTENDING THROUGH THE SHEET TO FORM A SERIES OF LOUVERS, SAID PORTIONS BEING DEPRESSED IN ONE SURFACE OF THE SHEET, SAID DEPRESSIONS CONTAINING A SUBSTANTIALLY OPAQUE LIGHTABSORBING MATERIAL DISPERSED IN A SOLID CARRIER AND CAPABLE OF ABSORBING AND REFLECTING A SUBSTANTIAL PROPORTION OF THE LIGHT TRAVELING THROUGH SAID PORTION IN A DIRECTION TOWARD THE SIDE OF SAID SHEET HAVING THE DEPRESSIONS FROM A LIGHT SOURCE ON THE OPPOSITE SIDE, WHEREBY THE EYES OF A VIEWER ON THE SIDE OF THE SHEET HAVING SAID DEPRESSIONS ARE SUBSTANTIALLY SHIELDED BY SAID OPAQUE MATERIAL AGAINST GLARE INCIDENT TO THE DIFFUSION OF LIGHT BY SAID CRYSTALLITES. 